The present invention relates to an interchangeable film back type camera, and more particularly to a film back adapted to be interchangeably mounted onto a camera body.
An interchangeable-film-back type camera is employed for taking pictures with the different types of films during photographing by replacing a film back carrying one type of. a film with other film back carrying other type of a film. A film back to be interchangeably mounted on a camera body is provided with an aperture, through which the photosensitive surface of a film held in a film back faces an aperture formed in a camera body. Further, a film back is provided with a detachable light-shielding plate made of metal for preventing a film from being exposed to light. The light-shielding plate is detached from a film back after a film back is mounted on a camera body and attached again to a film back before a film back is taken away from a camera body.
With the above light-shielding structure of a conventional film back, however, it has been a problem how and where a detached light-shielding plate is to be held, which sometimes resulted in loss or damage thereof.
It is therefore an object of the present invention to provide an improved film back capable of avoiding the aforementioned problems.
For the above purpose, in accordance with the present invention, there is provided a film back including a light-shielding curtain member which covers an aperture of the film back, and an operating member which moves the curtain member between the first position where the aperture is fully covered and the second position where the aperture is uncovered.
The curtain member is preferably wound on a spool member which is biased to be rotated in a direction to wind up the curtain member for moving the curtain member to the second position.
The operating member may comprise an operating knob secured to the leading end of the curtain member, and mounted on the rear side of the film back to be manually slidable in a limited range. The operating knob is preferable to be fit in an elongated slit formed on the rear side of the film back and extending in the direction of movement of the curtain member with allowing the relative sliding within the length of the slit.
The operating member may be held at the first position by means of a stop member arranged to detachably hold the operating knob at one end of the slit when the operating knob is moved thereto. On the other hand, the operating knob is held at the other end of the slit by the biasing force of the biasing member applied to the curtain member.
In another aspect of the present invention, there is provided an interchangeable film back type camera comprising a camera body and a film back interchangeably mounted on the camera body, which comprises:
a light shielding member provided in the film back to be movable between the first position where an aperture of the film back is fully shielded by the shielding member and the second position where the aperture is not shielded;
a coupling system which detachably couples the film back and the camera body; and
a safety lock member which disables detachment of the film back from the camera body in case the light shielding member is at the second position.
The coupling system may comprise:
a first coupling structure for pivotally coupling one side end of the film back and the corresponding side end of the camera body while allowing relative rotation; and
a second coupling structure including a lug member and a hook member, the hook member being moved for detachably engaging the lug member, one of the lug member and the hook member being provided at the other side end of the camera body while the other one is at the corresponding side end of the film back.
In the above constituted camera, the film back is coupled to the camera body at one side end thereof by the first coupling structure, and at the other side end by engaging the hook member with the lug member. Further, the safety lock member disables the movement of the hook member so as to prevent the hook member from being disengaged from the lug member.
The first coupling structure may comprise a pair of a pivot shaft member and a resilient hook member for detachably holding the pivot shaft while allowing relative rotation thereof, one of which is provided at the one side end of the camera body while the other one is at the corresponding side end of the film back.
The safety lock member preferably comprises an arm lever, one end of which faces the area where the hook member is moved while the other end faces the area where the light shielding member is moved, when the film back is mounted to the camera body. The arm lever should be arranged to be movable between the operative position where the arm lever intersects the area of the movement of the hook member and the retracted position where the arm lever does not intersect.
Further, the arm lever may be biased to move toward the operative position, and the one end of the arm lever is arranged to be moved toward the retracted position against the biasing force in case the light shielding member is at the first position thereof for allowing movement of the hook member to be disengaged from the lug member.